The Federal Bureau of Investigation (FBI) employed tools designed to be used against terrorists when going after two Chinese nationals for trying to steal genetically modified corn seeds and send them back to China.

The case against Mo Hailong and Mo Yun was brought after the FBI suspected the siblings of plotting to steal patented seeds from companies including DuPont Pioneer and Monsanto and ship them home so a Chinese agriculture company, the Beijing Dabeinong Technology Group, could grow genetically modified corn. In going after the brother and sister, and five others, the FBI invoked the Foreign Intelligence Surveillance Act (FISA), which is best known for being used to track down terrorists, so agents could gather evidence against the defendants.

Suspicion was first raised when Mo Hailong was found to be snooping around Iowa corn fields owned by Monsanto and Pioneer. The FBI began to investigate the Mos, tapping cellphone calls, planting audio recording devices in their cars and going through email. The bureau plans to have evidence introduced at the Mos’ trial that was gathered using FISA warrants.

“Stealing hybrid seeds enhanced with traits such as drought resistance doesn’t pose the same immediate threat as a suicide bomber, but the FBI treats economic espionage and similar trade secret theft as dangerous threats to national security,” Grant Rodgers wrote at the Des Moines Register.

Rodgers also reported that some attorneys say the Justice Department’s tactics “constitute an unprecedented, dangerous overreach on a case that is nothing more than a trade secret dispute.”

Faiza Patel, a national security expert with the Brennan Center for Justice at New York University’s law school, told Rodgers: “FISA was intended to capture information about national security-type threats. It wasn’t meant to capture ordinary crime, such as violating trade secrets.”

The FBI claims that theft of trade secrets has security implications. “By obtaining what it needs illegally, China avoids the expense and difficulty of basic research and unique product development,” Randall Coleman, an assistant director in the FBI’s counterintelligence division, told a terrorism subcommittee of the U.S. Senate Judiciary Committee last year.

Mo Hailong and Mo Yun could go to prison for up to 10 years if convicted. Five other suspects in the case are at large.